Calcium is the most abundant mineral in the body and plays both a structural and functional role in maintaining human health. While most of the body's calcium is stored in the bones and teeth, calcium also serves a critical role in processes such as vascular contraction and vasodilation, muscle function, nerve transmission, and hormonal secretion. The calcium ion is also a ubiquitous cellular messenger, and stimulates a variety of enzymes and other target proteins.
There are a number of factors that put people at risk for diseases associated with inadequate calcium intake. Calcium absorption decreases in adulthood and continues to decrease as people age. In aging adults, bone breakdown exceeds formation, resulting in bone loss. In women, menopause leads to bone loss because decreases in estrogen production both increase bone resorption and decrease calcium absorption. Negative effects on calcium balance have also been observed in amenorrhic women of childbearing age. Further, a number of people who avoid dairy products due to lactose intolerance or veganism are also at risk for calcium inadequacy. Bone health measures serve as a basis for deriving measures such as Recommended Dietary Allowances for calcium, and inadequate calcium intake increases the risk for osteoporosis, a disorder characterized by porous and fragile bones which affects more than 10 million U.S. adults. In addition to its effects on bone health, calcium intake has been proposed to have beneficial effects on reducing cardiovascular disease risk, lowering blood pressure, and prevention of colorectal cancer and prostate cancer.
Magnesium is another essential mineral in the body. About half of total body magnesium is found in bone, while the other half is found within body tissues. Magnesium is required for more than 300 biochemical reactions in the body, and is important for maintaining the function of muscles and nerves, supporting the immune system, maintaining bone health, regulating blood sugar levels, maintaining normal blood pressure, and playing a role in energy metabolism and protein synthesis. Dietary studies suggest that many Americans do not get adequate amounts of magnesium. As magnesium absorption is regulated by the intestines and excretion is regulated by the kidneys, conditions affecting these organs may result in magnesium deficiency. For example, medicines that affect the kidneys such as diuretics and some antibiotics and antineoplastic medications may cause excessive loss of magnesium. Diabetes may result in magnesium loss due to increased magnesium loss in urine due to hyperglycemia. Alcoholism is associated with low blood levels of magnesium, and individuals with chronic malabsorptive problems such as those with Chrohn's disease, gluten sensitive enteropathy, regional enteritis, or intestinal surgery are also at risk for magnesium deficiency.
Given the number of people at risk for calcium and magnesium deficiency, there is an ongoing need for effective dietary supplements that can provide or improve an intake of these minerals to help meet nutritional requirements while being convenient and easy to use for the consumer. There are many dietary supplements containing calcium and magnesium compounds that are commercially available or described in prior literature. The vast majority of these are solid dosage forms, such as tablets, capsules, or powders. Although these supplements are relatively inexpensive, they have some disadvantages. Absorption of the nutrients from these supplements tends to be quite variable, and large tablets or capsules are frequently not suitable for pediatric, geriatric and some patient populations. Liquid dosage forms of calcium and magnesium possess some advantages over the solid dosage forms in terms of better absorption, convenience of use and dosing flexibility, but are less commonly available. The liquid formulations tend to have stability limitations and are vulnerable to microbial growth in the absence of additional preservatives. Almost all marketed liquid formulations of calcium and magnesium are particulate suspensions that tend to settle, and carry a requirement to “shake well before use”. These products can have variable absorption, depending upon the suspension characteristics, and can lead to incorrect dosing if not shaken well prior to use. There are few liquid products where the calcium and magnesium are completely dissolved in water and present in an ionic state to provide optimal absorption upon ingestion. However, the calcium and magnesium mineral concentrations of such formulations are relatively low compared to those of the suspension liquid products, and thus require relatively large volume dosages to meet the recommended daily allowances. Thus, there is a need for improved liquid dietary supplement formulations where calcium and magnesium are present in relatively high concentrations, are completely dissolved, and are inherently stable and resistant to microbial growth.